Brachytherapy (from the Greek word brachys, meaning “short-distance”), also known as internal radiotherapy, scaled source radiotherapy, curietherapy or endocurietherapy, is a form of radiotherapy in which a radiation source is placed inside or next to the area requiring treatment. Brachytherapy is commonly used as an effective treatment for cervical, prostate, breast, and skin cancer and can also be used to treat tumors in many other body sites.
As the radiation sources can be precisely positioned at the tumor treatment site, brachytherapy enables a high dose of radiation to be applied to a small area. Furthermore, because the radiation sources are placed in or next to the target tumor, the sources maintain their position in relation to the tumor when the patient moves or if there is any movement of the tumor within the body. Therefore, the radiation sources remain accurately targeted. This enables clinicians to achieve a high level of dose conformity—i.e. ensuring the whole of the tumor receives an optimal level of radiation. It also reduces the risk of damage to healthy tissue, organs or structures around the tumor, thus enhancing the chance of cure and preservation of organ function.
The two main types of brachytherapy treatment in terms of the placement of the radioactive source are interstitial and contact. In the case of interstitial brachytherapy, the sources are placed directly in the target tissue of the affected site, such as the prostate or breast. Contact brachytherapy involves placement of the radiation source in a space next to the target tissue. This space may be a body cavity (intracavitary brachytherapy) such as the cervix, uterus or vagina; a body lumen (intraluminal brachytherapy) such as the trachea or esophagus; or externally (surface brachytherapy) such as the skin. A radiation source can also be placed in blood vessels (intravascular brachytherapy) for the treatment of coronary in-stent restenosis.
The dose rate of brachytherapy refers to the level or ‘intensity’ with which the radiation is delivered to the surrounding medium and is expressed in Grays per hour (Gy/h). Low-dose rate (LDR) brachytherapy involves implanting radiation sources that emit radiation at a rate of up to 2 Gy·hr-1. LDR brachytherapy is commonly used for cancers of the oral cavity, oropharynx, sarcomas and prostate cancer. Medium-dose rate (MDR) brachytherapy is characterized by a medium rate of dose delivery, ranging between 2 Gy·hr-1 to 12 Gy·hr-1. High-dose rate (HDR) brachytherapy is when the rate of dose delivery exceeds 12 Gy·hr-1. The most common applications of HDR brachytherapy are in tumors of the cervix, esophagus, lungs, breasts and prostate. Most HDR treatments are performed on an outpatient basis, but this is dependent on the treatment site.
Pulsed-dose rate (PDR) brachytherapy involves short pulses of radiation, typically once an hour, to simulate the overall rate and effectiveness of LDR treatment. Typical tumor sites treated by PDR brachytherapy are gynecological and head and neck cancers.
In order to accurately plan the brachytherapy procedure, a thorough clinical examination is performed to understand the characteristics of the tumor. In addition, a range of imaging modalities can be used to visualize the shape and size of the tumor and its relation to surrounding tissues and organs. These include x-ray radiography, ultrasound, computed axial tomography (CT or CAT) scans and magnetic resonance imaging (MRI). The data from many of these sources can be used to create a 3D visualization of the tumor and the surrounding tissues. Next, placement of the brachytherapy source applicators is determined by the clinical personnel. The source applicators are placed in the body and further imaged to ensure correct positioning of the applicators. Then, a ‘virtual’ patient and optimizing treatment plan is created. A 3D visualization is created of the patient and the applicators to refine the planned delivery of the radioactive sources. Last is the treatment delivery.
Prior to the treatment delivery, the radioactive seeds and needles must be ordered. The needles must be a custom gauge and the seeds come in different doses. The medical personnel must order the needle gauge and specifically determine the dose of each seed. Thereafter, the needles are inserted with the radiation seeds. The needles are then shipped to the medical personnel all over the country, when they are providing the treatment for the patient. The needles are shipped in big needle containers. The needle containers are covered with lead. This method of shielding increases the shipment cost to the patients and medical personnel. Furthermore, the problems that occur with the covering of the entire needles is radiation may leak, specifically, the covering of the needles may be removed or fall off of the needle package.
Therefore, one of ordinary skill in the art would appreciate that a method and apparatus be developed to reduce the shipment cost as well as provide a more effective way to enclose the radioactive seeds inside the surgical needles. In addition, a new method would be greatly appreciated to reduce the shipment cost as well to provide a more affordable health care treatment.